The subject matter of the present invention relates to a valve shifting system for shifting a conveying line between at least two additional conveying lines. Typically such a system is required when it is desired to transfer material flowing through a conveying line to one location so that it flows through a selected conveying line to another location.
The problem of shifting a conveying line between other conveying lines has been recognized for a long time as evidenced by U.S. Pat. No. 721,743 which was issued in 1903 to Richmond. In Richmond a swing tube section is connected to an inlet conveying line and the opposite end of the swing tube is slid in contact with a vertical plate from one outlet port, located through the plate, to another such outlet port during shifting between ports. In addition, these outlet ports are connected to outlet conveying lines. One problem arising with such a device is the poor sealing of the swing tube to the outlet port arising because the swing tube is slid into position instead of moving from a position away from the plate forward to the desired outlet port. Also problems exist in exactly aligning the swing tube with the outlet ports caused by oversliding the swing tube slightly past the ports or by undersliding the swing tube, which in either case results in misalignment. Since that time numerous other arrangements have been proposed to permit switching between conveying lines, but each proposed heretofore possesses one or more limitations, such as complexity, likelihood of misalignment, etc.
Therefore a need exists for a valve shifting system which is simple, reduces misalignment, which is capable of being used in applications where a first conveying line needs to be shifted to another conveying line which can be selected in the system from among two, three, four, five, or more such other conveying lines, and which is comparatively of inexpensive construction but rugged and serviceable.